A semiconductor device of the generic type is known from the document WO 01/93396, for example, which describes an optically pumped vertical emitter embodied in monolithically integrated fashion together with a pump radiation source, for example an edge emitting semiconductor laser.
In order to achieve a high pump efficiency, it is necessary for the pump wavelength to be smaller than the emission wavelength of the vertical emitter. The different wavelengths are achieved for example by means of different structures and materials compositions of pump radiation source and vertical emitter, respectively.
Such a semiconductor device can be produced for example by firstly growing the layers for the vertical emitter over the whole area on a substrate and subsequently partially etching said layers away again in laterally outer regions. In a second epitaxy step, the layers for the pump radiation source, for example an edge emitting semiconductor laser, are grown in the etched-away regions.
However, production by means of two separate epitaxy steps is relatively complex. Furthermore, care must be taken to ensure that a good optical transition is formed between the pump radiation source and the vertical emitter, in order that absorption losses at this location are kept small.
An optically pumped semiconductor device having a single continuous active layer with a quantum well structure is furthermore known from Gerhold et al., IEEE Journal of Quantum Electronics, Vol. 34, No. 3, 1998, pages 506 to 511. The quantum well structure of the active layer is intermixed in the laterally outer regions, so that radiation having a shorter wavelength is generated in this region in comparison with the central region, said radiation serving as pump radiation for the central region.
Since only a single active layer is formed, however, the pump wavelength can only be varied in a comparatively small range. Moreover, there is the risk of the optical properties of the semiconductor body being impaired by the intermixing of the quantum well structures in the laterally outer regions, which may lead to a reduction of the pump efficiency.